DESCRIPTION (Adapted from applicant's description): To further investigate the anomalous neural systems in autistic disorder as a phenotype for genetic analysis, the investigators will perform high- resolution three dimensional magnetic resonance imaging (MRI) scans in two childhood AD populations as the basis for subsequent basis for subsequent complete morphometric analysis for computation of volume of whole brain, individual substructures, hemispheric regions, and application of specialized method of cortical localization and parcellation.